/**
*      author: Y_Yao
*      created: 2025-03-15 20:11:37
**/

#include<bits/stdc++.h>

#define int LL
using namespace std;
using LL = long long;
const LL LLINF = 9e18;
const int INF = 0x3f3f3f3f;
const int N = 3e5 + 7;
int n;
int a[N];
int sum1[N],sum2[N];
unordered_map<int,int> mp1;
unordered_map<int,int> mp2;


void solve()
{
    cin >> n;
    for(int i = 1;i <= n;i++)
    {
        cin >> a[i];
        if(!mp1.count(a[i]))
        {
            sum1[i] = sum1[i-1] + 1;
        }
        else sum1[i] = sum1[i-1];
        mp1[a[i]]++;
    }
    for(int i = n;i >= 1;i--)
    {
        if(!mp2.count(a[i]))
        {
            sum2[i] = sum2[i+1] + 1;
        }
        else sum2[i] = sum2[i+1];
        mp2[a[i]]++;
    }
    int ans = 0;
    for(int i = 1;i <= n;i++)
    {
        int l = sum1[i];
        int r = sum2[i + 1];
        ans = max(ans,l + r);
    }
    cout << ans << endl;

}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    int t = 1;
    //cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}